Scientists often take an epidemiological approach to a phenomenon to discover clues about its cause and nature. This is not limited to medical diseases, the basic concept can apply to any episodic event.
Take UFO sightings – the phenomenon in question is people reporting that they saw something unidentified in the sky. We can generate some basic hypotheses about factors that might influence UFO sightings: the presence of objects to be observed, viewing conditions, number of people available to make observations, and priming (the idea of UFOs in the culture, say following a movie about UFOs or a case reported in the media).
As reported by The Economist, the National UFO Reporting Center has released statistics on UFO sightings by state and by time of day. The Economist has conveniently placed this data in an infographic, depicted right. They helpfully labeled the three periods of the day as working hours, drinking hours, and sleeping hours. As you can see, UFO reports peak during the drinking hours.
I am going to assume the article is tongue-in-cheek, but it is being spread around social media, sometimes in a manner that seems credulous.
I don’t doubt the data itself, but the labeling of the chart amounts to begging the question – calling the evening hours the “drinking hours” makes certain assumptions about cause and effect. A far simpler explanation for the peak of sightings in the evening is that night-time conditions are more conducive to seeing unidentified lights in the sky, and people are still awake.
The article cheekily states that aliens don’t disturb us while we sleep (don’t tell that to people who experience hypnagogia and interpret the experience as an alien abduction), but obviously people are simply not in a position to make observations while they sleep.
Therefore we don’t need to invoke alcohol consumption at all to explain the pattern seen in this data.
There are, however, patterns in the UFO data that . . .